A tibial component of this kind has been disclosed in the patents EP 0 864 306 A1 and WO 99/13804.
A feature common to these known tibial components is that on the exposed end face of the bearing post are disposed projections that extend radially outward. On the basis of this construction, to ensure that the only movement of the bearing body allowed on the associated tibial platform is rotational, it is necessary to provide a separate fixation screw as proposed in the document WO 99/13804; this prevents the translational movement of the bearing body on the tibial platform that is allowed in the original design. In the proposal according to WO 99/13804, so that the fixation screw can be screwed into the bearing post it must pass through the end face of the bearing body. Therefore, according to the state of the art, a separate component is needed to block translational movement, which makes the construction as a whole considerably more complicated and thus correspondingly more expensive. An additional disadvantage of the state of the art according to WO 99/13804 is that the fixation screw must pass through the bearing body, i.e., it must be screwed into the bearing post from the femoral side. This involves a not inconsiderable weakening of the bearing body. Furthermore, particles that have been detached by abrasion can migrate through the bearing body in both directions, from the tibial side to the femoral side and the reverse.